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| author | Oleg Nesterov <oleg@tv-sign.ru> | 2007-02-10 01:46:38 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-02-11 11:18:07 -0800 |
| commit | 8d06087714b78e8921bd30b5c64202fe80c47339 (patch) | |
| tree | fc55cbbf9fcdd2f9bed838b073f7828a1e78f636 /kernel/sysctl.c | |
| parent | c75fb88dbcc470e6041a20b1457b4835b9a0a48a (diff) | |
| download | linux-8d06087714b78e8921bd30b5c64202fe80c47339.tar.gz linux-8d06087714b78e8921bd30b5c64202fe80c47339.tar.bz2 linux-8d06087714b78e8921bd30b5c64202fe80c47339.zip | |
[PATCH] _proc_do_string(): fix short reads
If you try to read things like /proc/sys/kernel/osrelease with single-byte
reads, you get just one byte and then EOF. This is because _proc_do_string()
assumes that the caller is read()ing into a buffer which is large enough to
fit the whole string in a single hit.
Fix.
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/sysctl.c')
| -rw-r--r-- | kernel/sysctl.c | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 84cab0ce44d9..e0ac6cd79fcf 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -1686,13 +1686,12 @@ static int _proc_do_string(void* data, int maxlen, int write, size_t len; char __user *p; char c; - - if (!data || !maxlen || !*lenp || - (*ppos && !write)) { + + if (!data || !maxlen || !*lenp) { *lenp = 0; return 0; } - + if (write) { len = 0; p = buffer; @@ -1713,6 +1712,15 @@ static int _proc_do_string(void* data, int maxlen, int write, len = strlen(data); if (len > maxlen) len = maxlen; + + if (*ppos > len) { + *lenp = 0; + return 0; + } + + data += *ppos; + len -= *ppos; + if (len > *lenp) len = *lenp; if (len) |